Why Facebook, why?

About a week ago Facebook introduced a global “Like” button that you can put on any website. It sparked some controversy as some people don’t like the idea that Facebook is spreading like a cancer all over the internet as if they are the platform the web is built on.

I started looking into implementing this, and today I realised that the API for “open” graph specifies the meta tag with an attribute “property” this is not valid XHTML. Why couldn’t they just use the name attribute like everyone else? Why Facebook, why?